This time the problem lies (with apologies for another oxymoron) in an over-abundance of wit. Toltz's sharp intelligence isn't in doubt, but his discipline is. No single idea can appear in his book without another three snapping at its heels, jostling for space and attention. Hardly a paragraph concludes without a joke. Metaphor is piled over metaphor, aphorism upon aphorism, cynical observation on cynical observation, and philosophical conundrum on top of conundrum.

Sometimes the results are exhilarating, impressive, and/or hilarious. Loneliness is described as "the slow squeeze of testicles by a hand that has just been in a refrigerator". Eyes' pupils are like "broken pieces of night". The main narrator, Jasper Dean, tells us that he has "ears pressed flat against my head like they were waiting for someone to pass". The futility of trying to forget gets the following treatment: "When you put in that much effort to forget someone, the effort itself becomes a memory. Then you have to forget the forgetting and that too is memorable." And read this for an uncomfortable truth about prisons: "The state is always going about the business of introducing dangerous criminals to each other - they plunge them right into the network."

At other times, the boom-tish joking and constant clever-cleverness annoy. A tense moment is interrupted with the observation: "He scratched his tattoo. It wouldn't come off." A gun is retrieved from a sugar pot, seemingly only in order to set up the following tumbleweed-and-low-wind failure of a one-liner: "The gun was still there but the sugar was gone. There was nothing sweet about it any more." An already irritating essay about Hamlet is made yet more groan-inducing by this nugget of wisdom: "By the end of the play, everyone is dead, too bad for Shakespeare if he decided he later wanted to write a sequel."

The plot, meanwhile, is readily acknowledged to be a "scarcely credible sequence of disasters". It veers from the sublime, to the sublimely ridiculous, to the plain annoying. Following the disastrous attempts of Martin Dean to put the world to rights and the struggle of his son Jasper to escape his influence, the beginning at least is inspired. This is the story of Martin's half brother Terry Dean, a psychopathic criminal who becomes a folk hero by killing anyone who cheats at sport, and thus neatly comments on two of Australia's biggest obsessions: team games and the Ned Kelly-style hero. From here it launches into the creation of a handbook of crime; pitched battles between Algerian gangsters; a crazy scheme to make everyone in Australia a millionaire … The gleeful absurdity remains but the suspicion of pointlessness creeps in - especially by the time the heroes are hiding out in a remote village in Thailand, one of them smearing himself in "oil made of the fat melted from the chin of a woman who died in childbirth".

So, the book is a big jumble of mad ideas, crazed rants and surreal unlikelihoods. Not that that isn't the intention. As the title suggests, one of the central conceits concerns the many complex twists and turns within the character of a man and those that surround him. Toltz even provides a gloriously over-the-top metaphor to further make the point: Martin builds a house in the middle of a maze he creates in the outback, making him "a labyrinth in a labyrinth".

Less easy to forgive is the fact that in spite of its frequent brilliance the book grows dull. Too many jokes fall flat, too few of the characters ring true, and, while Toltz has a neat line in maxims, there's no real feeling of profundity. By the time the book stuttered to a close with a list of nine (count them!) aphorisms, I was wishing Toltz had provided a smaller fraction of this over-sized whole.